Selective Planting.—By selective planting we mean choosing the best plants and planting the seed from these plants with a view of improving the yield. In doing this we must not necessarily select the most perfect fruits or grains, but must select seeds from the best plants. A wheat plant should be selected not from its yield alone, but from its ability to stand disease and other unfavorable conditions. In 1862 a Mr. Fultz, of Pennsylvania, found three heads of beardless or bald wheat while passing through a large field of bearded wheat. These were probably mutants which had lost the chaff surrounding the kernel. Mr. Fultz picked them out, sowed them by themselves, and produced a quantity of wheat now known favorably all over the world as the Fultz wheat. In selecting wheat, for example, we might breed for a number of different characters, such as more starch, or more protein in the grain, a larger yield per acre, ability to stand cold or drought or to resist plant disease. Each of these characters would have to be sought for separately and could only be obtained after long and careful breeding. The work of Mendel (see page [257]) when applied to plant breeding will greatly shorten the time required to produce better plants of a given kind. By careful seed selection, some Western farmers have increased their wheat production by 25 per cent. This, if kept up all over the United States, would mean over $100,000,000 a year in the pockets of the farmers.
Hybridizing.—We have already seen that pollen from one flower may be carried to another of the same species, thus producing seeds. If pollen from one plant be placed on the pistil of another of an allied species or variety, fertilization may take place and new plants be eventually produced from the seeds. This process is known as hybridizing, and the plants produced by this process known as hybrids.
In hybridizing, all of the flower is removed at the line (W) except the pistil (P). Then pollen from another flower of a nearly related kind is placed on the pistil and the pollinated flower covered up with a paper bag. Can you explain why?
Hybrids are extremely variable, rarely breed from seeds, and often are apparently quite unlike either parent plant. They must be grown for several years, and all plants that do not resemble the desired variety must be killed off, if we expect to produce a hybrid that will breed more plants like itself. Luther Burbank, the great hybridizer of California, destroys tens of thousands of plants in order to get one or two with the characters which he wishes to preserve. Thus he is yearly adding to the wealth of this country by producing new plants or fruits of commercial value. A number of years ago he succeeded in growing a new variety of potato, which has already enriched the farmers of this country about $20,000,000. One of his varieties of black walnut trees, a very valuable hard wood, grows ten to twelve times as rapidly as ordinary black walnuts. With lumber yearly increasing in price, a quick growing tree becomes a very valuable commercial product. Among his famous hybrids are the plumcot, a cross between an apricot and a plum, his numerous varieties of berries and his splendid "Climax" plum, the result of a cross between a bitter Chinese plum and an edible Japanese plum. But none of Burbank's products grow from seeds; they are all produced asexually, from hybrids by some of the processes described in the next paragraph.
The Department of Agriculture and its Methods.—The Department of Agriculture is also doing splendid work in producing new varieties of oranges and lemons, of grain and various garden vegetables. The greatest possibilities have been shown by department workers to be open to the farmer or fruit grower through hybridizing, and by budding, grafting, or slipping.
Budding.—If a given tree, for example, produces a kind of fruit which is of excellent quality, it is possible sometimes to attach parts of the tree to another strong tree of the same species that may not bear good fruit. This is done by budding. A T-shaped incision is cut in the bark; a bud from the tree bearing the desired fruit is placed in the cut and bound in place. When a shoot from the embedded bud grows out the following spring, it is found to have all the characters of the tree from which it was taken.
Steps in budding. a, twig having suitable buds to use; b, method of cutting out bud; c, how the bark is cut; d, how the bark is opened; e, inserting the bud; f, the bud in place; g, the bud properly bound in place.
